Caption: Orchid petal surface (Dendrobium sp), scanning electron micrograph (SEM). Individual epidermal cells are packed tightly together. The orchid flower is typically has an outer whorl of three sepals, an inner whorl of three petals, and a single large column. When the flower opens, the sepals may become enlarged and colored. Dendrobium orchids are widely used as houseplants or for flower arrangements. Magnification: x120 when shortest axis printed at 25 millimetres.